UBA2014 NXP Semiconductors, UBA2014 Datasheet - Page 7

• Manufacturer Part Number: UBA2014
• Description: 600 V Driver Ic For Hf Fluorescent Lamps
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 11428
Product data sheet
8.10 Capacitive mode protection
8.11 Charge coupling
8.12 Design equations
8.9 Power-down mode
The Power-down mode will be entered if, at the end of the ignition time, the voltage at pin
LVS is above V
TR1 and TR2 will be non-conductive. The V
released from the Power-down mode by lowering the low-voltage supply below V
The signal across R16 also gives information about the switching behavior of the half
bridge. If, after the preheat state, the voltage across the ACM resistor (R16) does not
exceed the V
(CMD) assumes that the circuit is in the capacitive mode of operation. As a consequence
the frequency will directly be increased to f
the voltage at pin CSW until C
Due to parasitic capacitive coupling to the high voltage circuitry all pins are burdened with
a repetitive charge injection. Given the typical application the pins IREF and CF are
sensitive to this charge injection. For charge coupling of approximately 8 pC, a safe
functional operation of the IC is guaranteed, independent of the current level.
Charge coupling at current levels below 50 A will not interfere with the accuracy of the
V
Charge coupling at current levels below 20 A will not interfere with the accuracy of any
parameter.
The following design equations are used to calculate the desired preheat time, the
maximum ignition time, and the minimum and the maximum switching frequency.
Start of ignition is defined as the moment at which the measured lamp voltage crosses the
V
t
t
f
f
ign
ph
CS
min
max
lamp(fail)
, V
=
=
=
=
1.8
PCS
0.26
40.5 10
2.5
level; see
and V
------------------------- -
330 10
CMD
------------------------- -
330 10
f
C
min
lamp(fail)
CT
C
ACM
3
level during the non-overlap time, the Capacitive Mode Detection circuit
CT
Section
9 –
100 10
--------------------------- -
Rev. 02 — 12 September 2005
levels.
9 –
. In the Power-down mode the oscillator will be stopped and both
C
------------------- -
33 10
CF
R
------------------- -
33 10
IREF
R
8.8.
–
IREF
12
CSW
3
3
33 10
------------------- -
R
has been discharged to zero.
IREF
3
max
DD
. The frequency behavior is decoupled from
600 V driver IC for HF fluorescent lamps
supply is internally clamped. The circuit is
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
UBA2014
DD(reset)
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